#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/select.h>
#include <sys/wait.h>
#include "../common/function.h"
#define BUF_SIZE 100

int main(int argc, char *argv[])
{
    int serv_sock, clnt_sock;
    struct sockaddr_in serv_adr, clnt_adr;
    struct timeval timeout;
    fd_set reads, cpy_reads;
    
    socklen_t adr_sz;
    int fd_max, str_len, fd_num, i;
    char buf[BUF_SIZE];
    if (argc != 2) {
        printf("Usage : %s <port> \n", argv[0]);
        exit(1);
    }

    serv_sock = socket(PF_INET, SOCK_STREAM, 0);
    memset(&serv_adr, 0, sizeof(serv_adr));
    serv_adr.sin_family = AF_INET;
    serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
    serv_adr.sin_port = htons(atoi(argv[1]));

    if (bind(serv_sock, (struct sockaddr*) &serv_adr, sizeof(serv_adr)) == -1)
        error_handling("bind error");
    if (listen(serv_sock, 5) == -1)
        error_handling("listen error");
    
    FD_ZERO(&reads);
    FD_SET(serv_sock, &reads);
    fd_max = serv_sock;

    while(1)
    {
        cpy_reads = reads;
        timeout.tv_sec = 5;
        timeout.tv_usec = 5000;

        if ((fd_num = select(fd_max+1, &cpy_reads, 0, 0, &timeout)) == -1)
            break;
        if (fd_num == 0)
            continue;
        
        for (i = 0; i < fd_max + 1; i++)
        {
            if (FD_ISSET(i, &cpy_reads))
            {
                if (i == serv_sock) {
                    clnt_sock = accept(serv_sock, (struct sockaddr*)&clnt_adr, &adr_sz);
                FD_SET(clnt_sock, &reads);
                if (fd_max < clnt_sock)
                    fd_max = clnt_sock;
                printf("Connected client: %d \n", clnt_sock);
                } else {
                    str_len = read(i, buf, BUF_SIZE);
                    if (str_len == 0) {
                        FD_CLR(i,&reads);
                        close(i);
                        printf("Closed client: %d \n", i);
                    } else {
                        write(i, buf, str_len);
                    }
                }
            }
        }
    }
    close(serv_sock);
    return 0;
}